I. FIELD OF THE INVENTION
The invention relates to trailers to be towed behind two wheeled vehicles, especially those trailers having a single road wheel. In particular, the invention pertains to such a trailer provided with a novel hitch member to attach the trailer to a motorcycle, a novel adjustable trailer road wheel suspension system and means for urging the trailer downwardly while in use.
II. DESCRIPTION OF THE PRIOR ART
There are a number of prior art trailers adapted to be towed behind a motorcycle. One such prior art trailer incorporates a joint connecting the frame of the trailer with the towing motorcycle which includes two hinge axes, one of which is inclined upwardly and forwardly with respect to the road surface and the other of which is normally horizontal and also is perpendicular to the inclined hinge axis. In this device, when the towing motorcycle tilts as it does when in a turn, the forces transmitted to the trailer, which cause it to tilt with the motorcycle, are transmitted to and carried by the hinges of the joint connecting the trailer frame to the towing motorcycle. Depending on the weight being carried by the trailer, these forces could readily cause a distortion of the hinges, thus causing them to bind and thereby limiting their free pivoting movement about their axes, and in severe cases breaking the hinge.
Another prior art trailer includes a hitch incorporating two mutually perpendicular spindles, one spindle being disposed in the transverse horizontal plane of the trailer and the other being disposed in a vertical longitudinal plane of the trailer. Again, when the towing motorcycle is tilted from the vertical, as it will be in making a turn, the forces transmitted to the trailer to cause it to tilt with the motorcycle are carried entirely by the spindles. These forces can be great enough to deform the spindles, causing them to bind or even break.
A further prior art trailer includes a suspension system which is comprised generally of coiled springs disposed between a trailer bed and a frame upon which the trailer road wheel is mounted. These springs are illustrated as coil springs which are oriented to act as compression springs, i.e. they are loaded in the direction of their longitudinal axes.
Yet another prior art trailer teaches a road wheel suspension system having the road wheel mounted at one end of an arm, the arm being pivotally mounted between its ends to a frame of the trailer, and a coil spring disposed between the other end of the arm and the trailer frame. Again, the coil spring is deformable along its longitudinal axis by the forces being applied to it by the arm.
Further, none of these prior art trailer suspension systems are adjustable.
No prior art trailer known to me provides the combination and attributes of the present invention, viz. a trailer having a simple, inexpensive hitch member which transmits the forces from the towing motorcycle to the trailer to cause the trailer to follow the maneuvers of the towing motorcycle without transmitting these forces to the hinge of the hitch and provides a trailer road wheel suspension system which is adjustable to provide various suspension system spring rates to accommodate various weights carried by the trailer. The trailer is also formed to utilize wind forces generated as the motorcycle is moving to urge the trailer downwardly and to thereby aid in keeping the trailer from bouncing and skipping about as it is being towed at high speeds or in high winds.